Completed Sql4

[DhruvParashar246]

No description provided.

[super30admin]

1. Friend Requests II.sql:

   • Correctness: The solution correctly identifies the user(s) with the most friend requests by using a CTE to combine requester and accepter IDs and then counting occurrences. This approach is correct.
   • Time Complexity: O(n) for the UNION ALL and O(n) for the GROUP BY, making it O(n) overall where n is the number of records in RequestAccepted.
   • Space Complexity: O(n) for storing the CTE results.
   • Code Quality: The code is clean and readable. Using CTEs makes the logic clear. Consider adding comments to explain the purpose of each CTE.
   • Efficiency: The solution is efficient. No major optimizations needed.

2. League Statistics.sql:

   • Correctness: The solution correctly calculates league statistics by combining home and away matches and then aggregating the results. The CASE statement for points calculation is correct.
   • Time Complexity: O(n) for the UNION ALL and O(n) for the GROUP BY, making it O(n) overall where n is the number of matches.
   • Space Complexity: O(n) for storing the CTE results.
   • Code Quality: The code is well-structured. The commented-out SELECT statement should be removed to maintain cleanliness.
   • Efficiency: The solution is efficient. No major optimizations needed.

3. Sales Person.sql:

   • Correctness: The solution correctly identifies salespersons who have not sold any products to the company 'Red' using a NOT IN subquery. This approach is correct.
   • Time Complexity: O(n) for the subquery and O(m) for the main query, making it O(n + m) overall where n is the number of orders and m is the number of salespersons.
   • Space Complexity: O(n) for the subquery results.
   • Code Quality: The code is simple and effective. Consider using NOT EXISTS instead of NOT IN for better performance in some SQL engines.
   • Efficiency: The solution is efficient, but using NOT EXISTS might be more performant in certain scenarios.

4. The Number of Seniors and Juniors to Join the Company.sql:

   • Correctness: The solution correctly calculates the number of seniors and juniors that can be hired within the budget using a window function to calculate running sums. The logic is correct.
   • Time Complexity: O(n log n) for the window function and O(n) for the filtering, making it O(n log n) overall where n is the number of candidates.
   • Space Complexity: O(n) for storing the CTE results.
   • Code Quality: The code is well-structured and uses advanced SQL features effectively. The commented-out SELECT statement should be removed.
   • Efficiency: The solution is efficient. No major optimizations needed.

General Feedback:

• The student demonstrates a strong understanding of SQL and uses CTEs effectively to break down complex problems.
• The code is generally clean and readable, but removing commented-out code would improve cleanliness.
• Consider adding brief comments to explain the purpose of each CTE or complex logic, especially in more complex queries.
• The student could explore alternative approaches (e.g., NOT EXISTS instead of NOT IN) to improve performance in some cases.